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Comparison of Energy Efficiency and CO2 of Gasoline and Electric Vehicles

Many articles have been written about the comparison of the energy efficiency of gasoline and electric vehicles. Most such articles have various flaws. This article will avoid these flaws and will show, electric vehicles are more energy efficient than gasoline vehicles, on a source energy-to-wheel basis, which is the most rational way to make the comparison. Many studies fail to use the lower heating value of the fuel, or fail to use the correct heating value of the fuel.

Many studies calculate meter-to-wheel efficiencies of electric vehicles of about 70%, which compare favorably with the tank-to-wheel efficiencies of gasoline vehicles of about 22%, i.e., EVs are 3.2 times more efficient. But that is not even close to reality.

E10 fuel (90% gasoline/10% ethanol) has a source energy, which is reduced due to exploration, extraction, processing and transport, to become the primary energy fed to E10 vehicles. As a result, the energy fed to the tank has to be multiplied by 1.2639 to obtain source energy.

Electrical energy has a source energy, which is reduced due to exploration, extraction, processing and transport, to become the primary energy fed to power plants, which convert that energy into electricity, which after various losses, arrives at user meters. As a result, the energy fed to the meter has to be multiplied by 2.8776 to obtain source energy. After these factors are applied, the EV and E10 vehicles have values as shown in the below table. The below table is based on US 2013 CO2 emissions of 2053 million metric ton to match the available 2013 electricity generation data. See Table 8.

E10

Prius

mpg

28

34

40

52

kWh/65 miles, to wheels

16.67

16.67

16.67

16.67

Btu/kW

3412

3412

3412

3412

Btu/65 miles, to wheels

56878

56878

56878

56878

miles in one hour

65

65

65

65

Btu/gal

112114

112114

112114

112114

Btu/65 miles, T-t-W

260265

214336

182185

140143

eff, T-t-W

0.219

0.265

0.312

0.406

SE factor

1.2639

1.2639

1.2639

1.2639

eff, SE basis

0.173

0.210

0.247

0.321

gal/65 miles, T-t-W

2.321

1.912

1.625

1.250

Btu/65 miles, SE basis

328948

270899

230264

177126

lb CO2/gal, SE basis

23.95

23.95

23.95

23.95

lb CO2/mile, SE basis

0.86

0.70

0.60

0.46

g CO2/km, SE basis

241

199

169

130

g CO2/km, T-t-W

191

157

134

103

L of E10/100 km, T-t-W

8.40

6.92

5.88

4.52

EV

2013

kWh/65 miles, to wheels

16.67

eff, M-t-W

0.684

kWh/65 miles, M-t-W

24.371

kWh/mile

0.375

Btu/kW

3412

Btu/65 miles, M-t-W

83155

SE factor

2.8776

Btu/65 miles, SE basis

239287

lb CO2/kWh, SE basis

1.2712

lb CO2/mile, SE basis

0.477

g CO2/km, SE basis

134

Energy efficiency, SE basis

EV better than E10, %

27.3

11.7

EV worse than E10, %

3.9

35.1

CO2, SE basis

EV better than E10, %

44.3

32.3

20.4

EV worse than E10, %

3.5

Effect of a “Cleaner” Grid in 2016: If the 2016 CO2 emissions of 1821 MMt were used, and the 2016 electricity generation data were assumed to be about the same as in 2013, then the above 1.2712 would become 1.1275 and the EV CO2 emissions would become 0.423 lb/mile (119 g/km). Only E10 vehicles with about 45 mpg (5.23 L/100 km), or better, would have less CO2 emissions than an EV with a real-world, annual average meter to wheel of 0.375 kWh/mile (0.233 kWh/km). See below table and sections and Table 9.

EV

2016

kWh/65 miles, to wheels

16.670

eff, M-t-W

0.684

kWh/65 miles, M-t-W

24.371

kWh/mile

0.375

Btu/kW

3412

Btu/65 miles, M-t-W

83155

SE factor

2.8776

Btu/65 miles, SE basis

239287

lb CO2/kWh, SE basis

1.1275

lb CO2/mile, SE basis

0.423

g CO2/km, SE basis

119

Energy efficiency, SE basis

EV better than E10, %

27.3

11.7

EV worse than E10, %

3.9

35.1

CO2, SE basis

EV better than E10, %

50.6

40.0

29.4

EV worse than E10, %

8.2

High-efficiency Vehicles More Efficient Than Electric Vehicles: The table shows high-efficiency E10 vehicles, including hybrids, such as the 52 mpg,4.52 L/100 km Toyota Prius, have greater energy efficiency than EVs, and less CO2 emissions than EVs, on an SE basis. It would be much less costly and quicker to significantly increase the US hybrid fleet, than to build out the EV fleet, which is still in its infancy, and would require major, expensive changes to supporting infrastructures.

Tesla Model S: An upstate New York owner of a Tesla Model S measured the house meter kWh, vehicle meter kWh, and miles for one year. There was significant kWh/mile variation throughout the year. His annual average was 0.392 kWh/mile, M-t-W. The Model S has regenerative braking as a standard feature. The above analysis used an annual average of 0.375 kWh/mile, M-t-W, which means I used a higher EV efficiency than measured by this owner.

The EPA mpg gasoline equivalent is based on the energy content of gasoline. The energy obtainable from burning one US gallon of gasoline is 115,000 Btu, or 33.705 kWh, or 121.3 MJ. If a different fuel, such as E10, is used, then the Btu of that fuel is used to determine EPA MPGe.

EPA EV mileage = total miles/(fuel energy/energy/gal) = 65/(83154/112114) = 87.6 MPGe. The EPA deliberately ignores the US electrical system upstream SE factor and the E10 upstream SE factor. If the US SE factor were applied, the real mileage would be 87.6/2.8776 = 30.4 mpg, similar to the 28 mpg of the E10 vehicle, as one would expect.

The car manufacturers are in on the deal, because they are allowed to take those low MPGe numbers and average them into their CAFE mpg, making it look lower than it really is to befuddle the public, which is somewhat of a sham.

The official explanation of the EPA is that people are familiar with miles/gallon, and EPA decided to call it “miles/gallon equivalent”. Engineers may not be befuddled, but Joe Blow likely is. Just ask some average people what it means. They have no idea. That means what EPA came up with was confusing.

US-DOE/Argonne National Laboratories GREET Program: ANL wrote the Greenhouse gases, Regulated Emissions, and Energy use in Transportation, GREET, computer program. The program enables comparing the well-to-wheel efficiency of gasoline and electric vehicles. If I had used the program, the inputs would have been a fuel mix to power plants for determining the CO2 of the EV, and E10 for determining the CO2 of the E10 vehicle.

However, lacking sufficient familiarity with the GREET program, and always wanting to see equations, instead of just accepting printed results, readily available EIA data regarding CO2 emissions from the US electricity generating system, and EIA data regarding the generation of electricity, and data from various other sources, referenced in this article, were used to perform the analysis of this article.

NOTE: The article, “Is Ethanol a Cost Effective Solution to Climate Change?” shows, after a detailed analysis of the GREET computer program, the Argonne analysts relied on less-than-fully accurate international data bases, and overestimated well-to-wheel fossil fuels consumption (and associated CO2 equivalent emissions) of petroleum fuels by up to about 9%.

Quick Charging of Batteries: Because low-voltage (110V+) charging of batteries takes a long time,higher voltage (220V+) charging is often used, because it reduces charging times. However, that negatively impacts:

New England and EVs: With snow and ice, and hills, and dirt roads, and mud season, all-wheel drive vehicles, such as the Subaru Outback, SUVs, ¼-ton pick-ups, minivans, are a necessity in rural areas. There are a few EVs, such as the Tesla Model S, $80,000-$100,000, which offer road-clearance adjustment and all-wheel drive as options. Here is a list of EVs and Plug-in Hybrids. Very few have all-wheel drive and some of them cost 1.5 to 3 times as much as a Subaru Outback.

Driving an EV in winter, with 5 cm of snow, uphill, at low temperature, say – 10 C, with the heat pump heating the battery and the passenger cabin, would be slow going, unless the EV has a large capacity, kWh, battery. The additional stress causes increased battery aging and capacity loss.

Batteries likely will come down in cost, because of mass production, and weight, due to clever packaging (which would decrease rolling resistance), but the lithium-ion chemistry is pretty well maxed out, according to Musk, CEO of Tesla.

People switching from E10 vehicles to EVs likely will not happen anytime soon. There are no compelling CO2 reasons, as shown by the above table, unless the government compels people to do so, which would be a folly, as there are so many, less expensive ways, to reduce CO2. In fact, it would be best, if the government stopped interfering with the energy business.

Efficiency of US Light Duty Vehicles: LDVs are cars, SUVs, ¼-ton pick-ups, and minivans. The average efficiency of LDVs has not changed much these past 15 years. Even though new vehicle efficiency increased during the past 15 years, it caused just a very minor increase in the efficiency of all LDVs. See table. A similarly slow increase could be expected if EVs were to replace E10 vehicles.

However, if more LDVs were required to be hybrids (such as the Toyota Prius), which could be more rapidly implemented by manufacturers, then an efficiency increase of at least 25% could be expected during the next 15 years, etc. Toyota has a proven line-up of high-efficiency hybrids in various sizes and shapes. Other manufacturers could have the same.

LDVs

2000

2015

2000

2015

Better

mile/gal

mile/gal

L/100 km

L/100 km

%

Existing

20.00

22.00

11.76

10.69

10.0

New cars

28.50

36.40

8.25

6.46

27.7

New trucks

21.30

26.30

11.04

8.94

23.5

A Better Future Pathway: Future E10 vehicles likely would become more efficient, more quickly, and at much less cost, especially by increased use of hybrids, than:

– EVs could improve their efficiency, because lithium-ion technology is “just about maxed-out”, according to CEO Musk of Tesla. Such future EVs likely would become less costly, but not much more efficient.

– The US electrical system could reduce its CO2 intensity, kg CO2/kWh, such as with additional capacity, MW, build-outs of renewables and enlargements of the US electrical system. With higher-efficiency E10 vehicles, no such highly visible build-outs and enlargements would be needed. In fact, the capacity of the existing E10 fuel supply systems would be more than adequate for decades.

CO2 can be much less expensively reduced by:

– Making E10 vehicles more efficient

– Increased use of hybrid vehicles, such as Toyota Prius hybrids

– Increased building efficiency (having energy surplus buildings)

– Replacing existing nuclear plants with new nuclear plants, and, in New England,

At a steady velocity, on a level road, and with no wind from any direction, the propelling force of the engine offsets the external resisting forces acting on the vehicle, which are wind and rolling resistance.

Wind Resistance: The wind resistance of a medium-size vehicle was calculated using 0.5*c*A*d*V^2, where; c is drag coefficient, 0.32; A is cross-sectional area of vehicle, 2.600 m2; d is air density, 1.293 kg/m3, V is velocity, 104.607 km/h. The wind resistance is 454 newton. See Table 2.

Wind + Rolling Resistance: The useful power to the wheels, kW, was calculated using f, the total of wind and rolling resistance, 577 N; d, the distance travelled in one hour, 104.607 km; J = N*m, the work done, 60,331,767; t, the time 3600, seconds; W = J/s = 16759, or 16.67 kW. See Table 4.

Table 4

Units

Units

Wind + Rolling

f

577

N

129.612

lb force

Distance

d

104.607

km

343,195

ft

Work done

f*d

60,331,767

N.m = J

44,482,152

ft.lb force

Time

t

3600

s

3600

s

Watt

16759

W= J/s

16759

watt

Useful power

16.67

kW

16.67

kW

The Fuel: The vehicle is assumed to use E10, a mixture of 90% gasoline and 10% ethanol. Its lower heating value is 31.25 MJ/L. In engines, the LHV must be used. See Tables 5 and 6.

NOTE: The UK, cleanairchoice and GREET claim the factor is 1.203, 1.23 and 1.2568, respectively. In this analysis 1.2639 was used which attributes more CO2eq to E10 vehicles, which makes EVs look better, in comparison. See Table 2 in second URL and Page 8 in third URL.

Source Factor for US Electrical System: Various fuels, extracted from the earth, are fed to US electrical power plants. For exploration and extraction mostly diesel is used, for processing mostly diesel, gas and electricity are used, and for transport mostly diesel is used.

Table 7 shows the well-to-pump source factor for E10 is about 1.2639. The well-to-user source factor for gas and the mine/well-to-meter source factor for electricity are about 1.090 and 2.8776, respectively.

Also there is the energy consumed for O&M and on-going replacements/upgrading of the infrastructures used for exploration, extraction, processing and transport of the source energy that is converted to primary energy for the US economy. The US electrical system uses about 40% of all primary energy.

This results in an upstream factor of the US electrical system of about 1.08, i.e., the equivalent of about 8% of the source energy is used to obtain the primary energy fed to power plants. That 8% usage causes CO2 emissions. See Table 8. Excluded is the embodied energy of all the required infrastructures.

The Source-to-Wheel Efficiency of an EV

The US economy was supplied with about 25,451.00 TWh of primary energy in 2013. See Table 8. In this analysis, I used the 2013 emission data in conjunction with the 2013 electricity generation data.

The EIA 2013 emissions data is higher than at present, due to gas replacing coal. It is ironic, I could find the 2016 GERMAN electricity generation data, but not the 2016 US data.

German 2016 Electrical Data: Here are the corresponding numbers for Germany. In 2016, domestic electricity consumption = gross generation (648.4), less self-use (30), less net exports (53.7), less transmission and distribution (30), less pumped storage and misc. (19.4), = about 515.3 TWh at user meters. (CO2 of the gross generation) / (515.3 TWh) = grid CO2 intensity at the meter, which should be multiplied by the kWh drawn by an EV. However, this CO2 is based on primary energy grid intensity. It has to be adjusted by a factor to get source energy grid intensity, similar to the Table 8 procedure.

CO2 Emission Reduction Due to less Coal and More Natural Gas Combustion: The URL shows the unusually rapid decrease of CO2 emissions during 2015 and 2016. Such a rapid decrease likely will not occur during the next few years, as natural gas prices likely will increase due to exports, and as changes in EPA rules likely will cause fewer coal plants to close. A “cleaner” US grid would mean EVs would compare more favorable with E10 vehicles regarding emissions. See Table 9.

Thank Willem for the Post!

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Willem, you are to be commended on your diligent pursuit of the truth. It’s a lot of hard work, and as you know – the devil is in the details.

But you’re barely scratching the surface. The U.S. DOE has an ongoing, comprehensive analysis of full-spectrum, well-to-wheels emissions for every conceivable fuel and powertrain combination known as “The Greenhouse Gases, Regulated Emissions, and Energy use in Transportation Model” (under the tortured acronym of GREET). The following list describes only updates to the 2016 version of the model:

As you can see, the model shows an EV creating 2 grams/mi fewer GHG emissions than E10 gasoline. Not that impressive. But for the electricity generation mix I had entered for this scenario, nearly half came from coal (in California in 2017, less than 8% comes from coal).

Highly recommended, if you use Excel, to download and run it yourself (it gets addictive).

I’m suspicious of any model with hidden calculations, as are the scientists at Argonne. That’s why all of the calculations in both the Excel version of GREET and online are in full view.

I don’t know there are errors in your calculations, I suspect they’re 100% accurate. That your model represents “electricity arriving at the meter (after all losses)” is inaccurate – you’re considering a fraction of the criteria necessary to make such a calculation.

I’ve met the team which developed GREET – they are single-minded about the job before them. When I asked a team leader why nuclear plants are being closed, his reply was “we don’t consider politics or policy matters.” That’s socialism at work, and why you’ll never get an honest answer about energy from the private sector.

And why I won’t be surprised if the GREET model disappears during the Trump administration’s tenure or assumptions disappear from view, replaced by “alternative assumptions” based on “alternative facts”.

Seems like this is missing that EVs are the killer app for renewables — they will soak up the excess power during peak wind or sunshine and use it for transportation, and the used batteries will serve as backup supplies in homes, businesses, and utilities.

Take Tesla’s Gigafactory, with a capacity of 50 GWh of battery packs per year. Average grid load in the USA is about 450 GW. One Gigafactory-year’s worth of battery packs could support the average US grid load for…

about 6 minutes 40 seconds. After 9 years of production, you could buffer a whole HOUR! /sarc

The battery systems currently used mostly are for regulation, when many solar systems on a grid would cause too much disturbance, and for peak shaving, which works only if on and off peak rates are wide apart, and for reducing the capacity and grid charges imposed by a grid operator on a utility.

Several utilities in New England started up battery systems of about 4 MW/8 MWh capacity @ $800/kWh-$1600/kWh, for those uses, instead of using a quick-starting diesel generator, which they have been doing for decades, as part of the “microgrid/islanding” rah-rah.

Nice article. Always a pleasure to see honest and informed numeracy brought to bear on policy issues. Even it there’s room to challenge some of the numbers presented or omitted, at least the numbers are there and the assumptions are spelled out. The quality of the debate is enhanced.

I won’t weigh in about the differences between the GREET model that Bob recommends and the model that Willem put together. But Willem notes that he does not trust “Excel programs of which I have not seen the equations and assumptions,” Fair enough, but why not download the spreadsheet and take a look? The equations should be there, and one can generally figure out the assumptions. Spreadsheets aren’t rocket science.

What I’m more interested in is the issue of applying the current mix of generation resources to calculate emissions for electric vehicles. As it happens, most of the individuals I know of who drive electric cars have solar panels on their roofs, and do most of their vehicle charging at home. Granted, I live in Tesla country, and Tesla owners are a preselected lot. But Hops’ observation about vehicle charging being the “killer app” for renewables still stands. And a rigorous analysis of the effective carbon emissions of electric vehicles needs to consider not the current raw mix of generation sources, but rather the marginal effect of EV sales on the generation mix. That’s assuming that anyone can figure a way to calculate the marginal effect.

I also wonder about Willem’s assertion that “future E10 vehicles likely will become more efficient more quickly, than the US electrical system will reduce its CO2 intensity, lb CO2/kWh.” Could be, but it’s not obvious to me. In fact, I rather expect the opposite. I think we’re approaching an inflection point, where the rate of decarbonization of the electricity supply will accelerate noticeably.

Be that as it may, I think it’s important to keep in mind that what we need to do is not to reduce carbon emissions by some target amount ‘X’, after which we’ll be fine. If ‘X’ is any value less than 100%, then we won’t be fine; we (or our children) will just take a bit longer to hang. So, yes, electric vehicles do have indirect carbon emissions, but as the electricity supply shifts to lower carbon intensity, the carbon intensity of the electric vehicle fleet shifts with it. The same cannot be said for the E10 vehicle fleet.

Willem,
You forget to calculate the far more important benefit of electric cars:
The much lower emissions of small particles*) as that kills people.
_______
*) Particulate matter (PM) causes a life shortening of ~2 years for people living in city centers with busy traffic, or living along busy highways (EU study)!
So nowadays older cars and diesel cars are no longer allowed in many cities in Germany and also in some cities of NL, etc.

Thus extending EPs calculation to 30 minutes from six. Hundreds of giga factories are required to make a grid sized storage play, and then some new facility distribute, and collect, millions of tons of battery. Don’t forget the associated expansion of lithium ore. The price is rising.

Also, if Tesla does build four more, they lock in current battery performance within 5% or so for the following decade, maybe two. The latest, greatest laboratory battery by press release simply won’t matter.

I agree that going to hybrids ASAP will have the most immediate impact on reducing emissions. I’m on record predicting that in the near future (5 – 10 year timespan) virtually ALL new production vehicles will be either pure BEVs or hybrids. They will have electric drive systems, because once the supply chains and production lines are established for it, electric drive delivers better performance and reliability at potentially lower cost than mechanical drive.

In this case, “performance” includes not just torque and acceleration, but precise control of torque to individual wheels for features like traction and skid control and enhanced cornering. Those features have all been implemented for high-end mechanical drives, but there they cost more and are clumsier. With electric drives, they’re just controller firmware. Those benefits are over and above regenerative braking and non-idling that give hybrids superior mileage.

Given the above, the issue becomes how big to make the hybrid drive batteries and whether to include plug-in capability. For me, it’s a no-brainer in favor of plug-in capability. Statistically, it only takes 10 – 15 kWh of battery to enable more than 50% of miles driven in battery-electric mode. 10 – 15 kWh isn’t exactly trivial, but it’s a hell of a lot less than the 100 kWh that pure BEVs are trending toward. With 10 – 15 kWh of storage, the per-mile driving cost plunges and the effective long term mileage gets into 100 mpg range.

Also, with that much electric capacity, emission reductions for transportation would benefit from de-carbonization of the grid.

Particulate matter (PM) emissions by power plants are very insignificant compared to that of traffic. Nowadays power plants here are obliged to filter all PM out of their exhaust gasses. They use a.o. cycloned, electrostatic filters, etc.

Dutch life expectancy is almost two years higher than that of USA…
Furthermore USA spends substantial bigger part of its GDP for health care than Netherlands (in 2010: USA, 16.2%; NL, 10.8%).
So relevant facts indicate the opposite of your assumption:
“NL being too crowded to remain healthy.”

Though it’s also clear that US citizens get less value for their health care money (also corrected for GDP/PP). Probably because US health care is reigned by huge oligarchical private enterprises which make good profits.

Can confirm. Data point: my car maxes out at mid-high 20 miles all-electric range in optimal weather, but I’m achieving well over 100 MPG average. (The car reports 131.3 MPG lifetime as of getting home this evening.) It does this with less than 8 kWh of battery.

Down at the actual hybrid end, we have a lot more options than just batteries. Ultracaps are great for high power/mass and help relieve compromises that engines have to make to “driveability” by sacrificing efficiency. If you’ve got a fat energy buffer that gives instant response, your engine can lag like crazy and the driver doesn’t care. If the designer can go all-in for efficiency and emissions they can both be quite a bit better.

The EPA states, with a straight face, the EV uses the energy equivalent of 87.73/118.28 = 0.742 gallons of E10 to go 65 miles. Thus the “phony EPA mileage” is 65/0.742 = 87.65 mpg. The car manufacturers are in on the deal, because they are allowed take those high mpg numbers and average them into their CAFE mpg, making it look higher than it really is to befuddle the public, which is somewhat of a sham.

The EPA deliberately ignores the upstream factor of 2.995 of the US electrical system. If that factor were applied, the real-world mileage would be 87.65/2.995 = 29.3 mpg. My calculation puts real numbers on a reality.

The official explanation of the EPA is that people are familiar with mpg, and EPA decided to call it “mpg equivalent”. Engineers may not be befuddled, but Joe Blow likely is. Just ask some average people what it means. They have no idea. That means what EPA came up with was confusing.

It is intuitively obvious an E10 vehicle and an equal weight EV, going 65 miles for 1 hour, would have about the same wind and rolling resistance, and therefore about the same energy to go from a to b, and therefore the same mpg. To say one has about 3 times the mileage, equivalent or not, is a deception.

I know that the mileage that is displayed on the car console (for the Prius, anyway) is a straightforward “miles driven / gallons consumed” since reset. For a plug-in, that number would obviously vary a lot depending on driving pattern. (It would go down substantially, e.g., if the car were driven on long trips, with little opportunity for charging, and would go up if it were driven on a lot of short trips with recharging in between most trips.)

My assumption — and that’s all it is — has been that the EPA rating was calculated on the basis of a standardized driving cycle that accounted for length of trips and opportunities for recharging. That’s what would make sense, and it’s consistent with the standardized driving cycles used to calculate figures for “city driving” and “highway driving” for non plug-in vehicles. But I’ve never looked into it.

I’ll raise a separate flag about trying to compare technologies on the basis of “primary energy” consumed. A megajoule is precisely defined in physics, but “primary energy” is a fuzzy concept. What’s the “primary energy” consumption for hot water from a solar thermal collector? And does it really make sense to equate a unit of thermal energy from coal with a one from natural gas or one from cow dung?

What really matters in terms of transportation efficiency and global warming is GHG emissions per distance travelled. The significant fact about E10 is that for a given vehicle make and model, that number will be relatively constant over the life of the vehicle — and will never be zero. For a BEV or plug-in hybrid, the number will depend on the carbon intensity of the charging source. It will decline as the carbon intensity of the grid in its region declines, or go to zero if the vehicle is charged exclusively from solar panels.

The latter isn’t improbable — at least in California — since in addition to rooftop solar on vehicle owners homes, there’s a trend for businesses to install solar panels in their parking lots. Free vehicle charging for employees during work hours is a nice perk that appeals to workers of the type that many companies here want to attract. (Not to mention being good for corporate image in California’s culture.)

I put it on the Kill-A-Watt once and it took about 7.5 kWh from the wall. (Okay, the post in the garage.) IOW it’s about 300 Wh/mile depending how I drive it.

What this incurs in emissions depends on the generation mix of the moment. If the marginal watt is coming from the 3400 MW of coal-fired plants in Monroe, it’s one thing. If it’s coming from the Donald C. Cook nuclear plant or the wind farms in Berrien county, it’s close to zero. If it’s coming from the Midland Cogeneration Venture it’s intermediate. If it’s coming from the pumped storage station at Ludington, it’s perhaps a 25% multiplier over whatever was used to fill it (probably wind or nuclear power these days, so also close to zero).

If we figure the emissions of a CCGT plant running in load-following mode at 400 gCO2/kWh, that plant is generating the marginal watt, and 300 Wh/mile, net emissions for the vehicle come to 120 gCO2/mile or about 75 gCO2/km. If we allow 30% non-emitting generation and credit the vehicle with that, it falls to 84 gCO2/mile. Pegging the emissions of E10 at 17.68 lbs (8.018 kg) per gallon, this is equivalent to an E10 vehicle achieving 66.8/95.5 MPG respectively.

Thanks Willem. Here’s one I will hand to you: the inefficiency of EVs in cold weather.

I think we’d both conclude that EVs can produce significant benefits in the right circumstances, and that gasoline/E10 vehicles are less dependent on circumstance.

A study came out a few years ago by a national environmental org (forget which one) which showed EVs were significantly worse for emissions in select parts of the country (basically, the Southeast – coal country). There was a flurry of denial in the EV community, but try as I might I could not fault the conclusions they drew therein.

I would like to think in the bigger picture – where government has more say in the collective emissions we generate, as it should – generating our energy collectively from point sources like power plants enables us to improve everyone’s emissions en masse, and not rely on individual incentive. When it comes to finding solutions to societal problems, I don’t believe we can count on the judgment of individuals to carry the day.

When it comes to finding solutions to societal problems, I don’t believe we can count on the judgment of individuals to carry the day.

Hoo boy! As it happens, I agree with you on that. But you’re poking at a hornets’ nest. It’s certain to raise the hackles of libertarians and small-government conservatives. As perhaps it should.

I’m not unsympathetic with the libertarians and small-government conservatives. My dad was a consulting engineer; he constantly railed against the idiocy of petty bureaucrats and the way blind code compliance inflated costs for projects in situations where compliance wasn’t functionally necessary. He hated what we now call the “nanny state”. His views rubbed off on me. For much of my life, I identified as libertarian.

I haven’t exactly changed my mind about those views. Now, however, I try to see things from a wider perspective. I look at society and the world in terms of system dynamics and game theory, rejecting ideologies as “what one falls back on in the absence of science and honest attempts to understand the issues”. It’s a pragmatic POV that starts with values and focuses on what will actually work to advance those values.

The tension between the interests of the individual vs. those of the group is incredibly fundamental. It has literally shaped the evolution of life on the planet. When you look deeply, the “prisoner’s dilemma” turns up everywhere. Evolution is just as much about cooperation and enabling win-win strategies as it is about competition and being a more successful predator.

So what works for solving societal problems when the interests of society collide with the short-term interests of individuals? Regulations are necessary. However, in formulating the regulations, one needs to be mindful of how they can be gamed. Engineering’s KISS principle (“keep it simple, stupid”) becomes supremely important. As a policy-maker, resist the temptation to specify solutions. Focus on incentive structures and alignment of incentives. People are very good at grasping incentive structures, and figuring out how to benefit from them.

Saw an interview recently with a Tesla executive talking about the cost and capacity of batteries from the Gigafactory for Model 3. He said that they would be 30% cheaper (per kWh) with 30% higher energy density. IOW, the same cost per kg, but 30% fewer kg needed to do the same job.

His explanation should be a cautionary note for those counting on continued exponential improvement in the economics of battery storage. It was simple: once you’ve gotten to high production volumes with factory equipment designed and optimized for the production task, then cost of product becomes proportional to mass, regardless of complexity. (More properly, cost of product becomes dominated by the cost of raw source materials. A kilo of platinum is always going to cost far more than a kilo of iron — or of dirt.)

He didn’t say it, but the message I heard was that with the gigafactory, Tesla is now down near the limits imposed by raw materials and battery chemistry. Battery lifetimes will likely improve, and tweaks to the electrolyte and electrode structures will likely yield further gains in energy density. But the gains won’t be dramatic.

Hmmm. Does that shed a new light on Musk’s latest venture? Is his “Boring company” perhaps a covert sally into mining technology? It does kinda fit with his interest in Mars colonies.

Willem, very well written and detailed article as usual. The following are a few issues that could impact and increasingly support your conclusions: 1) my detailed analysis of the GREET model well-to-wheel (WTW) calculations (re. my past TEC article: “Is Ethanol a Cost Effective Solution to Climate Change?” http://www.theenergycollective.com/jemiller_ep/172526/ethanol-cost-effec... ) which clearly showed that the Argonne folks relied on less-than-fully accurate international data bases, and overestimated WTW fossil fuels consumption (and associated carbon equivalent emissions) of petroleum fuels by up to about 9%., 2) what is often overlooked in evaluating EV energy usage and efficiency is the significant impact of ambient (battery) temperatures; which deteriorate quite significantly during cold winter environments (100 degree F). This factor also affects batteries’ capacities and lifespans. And, 3) the negative impacts of higher charging voltages, capacities and cycles (longer term charging frequencies) on battery charging efficiencies and full-available charge capacities. Higher voltage (220V+) definitely reduces charging times, but unfortunately, negatively impacts overall charging efficiencies and wear on batteries’ capacities. Those who perceived that EV batteries can be effectively used as residential/commercial backup battery capacities in order to directionally increase the capacity factors of intermediate solar and wind power, are going to be in for a big surprise as to the efficiency and wear on their EV battery packs; and shortened life’s/charging capacities’ impacts. Under these circumstances, EV owners will be very surprised as to the actual efficiencies and added cost of resultant shorten battery life’s.

Roger, agree the KISS principle can be equally effective at constructing regulations as it is in engineering, if not more so.

That’s why reknowned climatologist James Hansen has been an advocate (some say founder) of the revenue-neutral carbon tax, aka “fee and dividend”. In Hansen’s version, a tax directly proportional to its molar carbon is added to any quantity of fuel extracted in or imported to a jurisdiction. Once a month, after deducting administrative fees, revenues are divided and distributed equally to all citizens. If your consumption is less than average, you make money. If more, your lose (taxes you pay at the pump will be more than your refund check).

KISS – it doesn’t get much simpler than that. And it works – British Columbia’s RNT has reduced gasoline consumption by 17%. Then why doesn’t the U.S. have a revenue-neutral carbon tax?

It would work too well – it would limit the profit potential of selling gasoline. There is your head-to-head collision of the interests of society with the short term interests of individuals, or corporations, or any special interest. If we permit self-interest to rule the day, we might as well give up on climate change – it is, quite literally, hopeless.

Simply-worded regulations are the worst of all for corporations, because they introduce the wild card of human judgment – there’s a judge somewhere who will interpret them, and quite possibly not in the corporation’s best interest. So today teams of lawyers construct reams of law, with carefully-designed loopholes to maximize profit.

In sum, these laws categorically defy public interest. My favorite example is the Energy Act of 2005, which repealed the Public Utility Holding Company Act of 1935 (PUHCA). EnACT2005 is a monstrous, 551-page behemoth which very specifically eliminated public protections inherent in the 59-page PUHCA. To restore some sanity to this situation, a start would be assigning word and amendment limits to any law before Congress.

And of course, Citizens United has got to go. Representative democracy in the U.S. has always been a tenuous balance of capitalism (self interest) and socialism (public interest). Citizen’s United has upset that balance by rendering public interest moot – it’s become a battle between exclusively private interests, one in which laws are shaped by campaign contributions instead of popular vote.

Interestingly, the 1802 standoff between Hamiltonian Federalists and Jeffersonian Republicans was identical, in both ideology and acrimony, to today’s Democrat – Republican split. We can hope for a stalemate, but never the twain shall agree.

“Nothing “phony” about it – it’s very honest and simple, and serves a narrow purpose.”

The official explanation of the EPA is that people are familiar with mpg and EPA decided to call it “mpg equivalent”.

You and I are not befuddled, but Joe Blow is. Just ask some average people what it means. They have no idea. That means what EPA came up with was confusing.

But manufactures can take those high mpg numbers and average them into their CAFE, which is somewhat of a sham.

They and EPA know it, but the general public has no idea what is going on.

My calculation may not be so simple, but it is certainly honest as it put real numbers on a reality.

It is intuitively obvious an E10 vehicle and an equal weight EV, going 65 miles for 1 hour, would have about the same wind and rolling resistance, and therefore about the same energy to go from a to b, and therefore the same mpg.

To say one has about 3 times the mileage, equivalent or not, is a deception.

Willem, you and EP are comparing two different quantities: energy and power.

Strictly speaking energy on a grid does not “travel” at the speed of light. Changes in power – the rate of transfer of energy – do, and it’s very possible to track them. SCADA networks at independent system operators record power changes at grid junctions every second of every day and, with some accounting, can determine with a fair degree of accuracy the sources of energy on a grid. That’s how generators get paid.

Willem, I’m confused. The reasons you give for why it makes sense to equate units of thermal energy from sources with very different characteristics are exactly the reasons I’d use to argue that they shouldn’t be equated.

Did you perhaps take “make sense to equate” as “make sense to weigh”? I.e., “make sense to consider the differences”?

Every generator connected to the grid is monitored by the computers of the grid operator.

The operator knows the kWh fed into the grid to one to 3 decimals. That is how owners of generators get CREDITED.
The owners get PAID by whatever entity the owners have PPAs. The operator CREDIT slip is proof of delivery.

Once fed into the grid, the energy travels at near the speed of light, as electromagnetic waves, 180 miles in 0.001 second, i.e., it is all over the place and cannot be traced.

The electrons vibrate in place at 60 cycles per second, they are not going anywhere. OK, they move at less than one inch per second.

If you know the sources of energy fed into a grid, you know what comes out. There’s is no net surplus, otherwise by the first law of thermodynamics lines would melt from their poles. The mix going into everyone’s meter is exactly what is going into the grid at that time – nothing “generic” about it.

Energy is fed into the grid over time, not instantaneously. If one kW is added for one hour, the total energy transferred is one kWh. Transferring energy through a grid instantaneously would require an infinite amount of power:

A point that I’ve made elsewhere is that a significant amount of EV charging is done from solar energy that doesn’t get to the grid. I don’t know how much; I’ve never seen specific statistics. But on the basis of very rough and unscientific sampling from California EV owners I happen to know, it could easily be half.

Even the indirect carbon emissions from EVs / PHEVs charged from grid will differ depending on when the charging is done. If it’s done while regional load is dropping, it will reduce the drop, and sometimes avoid the need for cycling of a dispatchable unit. Since nearly all dispatchable resources (other than storage) are inefficient during startup and shutdown, avoiding the need to cycle is good. It reduces operating costs and lowers emissions per kWh.

To reap those benefits, however, signaling between the system operator and the charging units is needed. A form of “smart grid”.

Roger,
Batteries likely will come down in cost, because of mass production, and weight, due to clever packaging (which would decrease rolling resistance), but the lithium-ion chemistry is pretty well maxed out, according to Musk.

It’s the next watt of generation that will be added if demand increases. It’s what determines the incremental change in emissions from adding load. This works the other way also; the Joe Wheatley analysis of wind power in Ireland showed that the incremental decrease in emissions from adding wind was far less than 1:1.

How is this marginal watt so special, that it does not need to be treated as having to obey the laws of physics.

About those laws of physics…

Transmission lines have impedance. The higher the impedance, the less power flows through them for a given set of conditions between the ends. Ceteris paribus, longer lines have higher impedance. This means that distant generators will contribute less to a load than a local generator. Physics says that Iowa wind power isn’t going to contribute significantly to New York consumption given an AC grid in between (point-to-point HVDC is another matter).

This means that the emissions from charging an EV depend substantially on where it’s charged. Also when, because in most places that aren’t using e.g. 100% hydropower the marginal watt comes from different generators at different times of day.

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